Performance Analysis of Multi-User Uplink NOMA With Low Complex RS-OSIC Detector

Non-orthogonal multiple access (NOMA) is one of the key technique to improve upon the spectral efficiency required for fifth generation (5G) mobile networks. A severe inter-user interference is encountered during the detection process in the uplink (UL) NOMA scenario which leads to the imperfect successive interference cancellation (SIC) thereby resulting in extreme SIC error propagation. This paper investigates a novel reliable-symbol based ordered-successive interference cancellation (RS-OSIC) detection method for UL NOMA system. The proposed system model overcomes the detrimental effects of the imperfect SIC in terms of the error propagation. In particular, the RS-OSIC detection scheme is a low complexity scheme and is proposed for the considered UL NOMA system to offer enhanced quality of service (QoS) and improved data reliability while serving large number of end users. To get the better insight of the proposed RS-OSIC algorithm, the bit error rate (BER) performance of the same is presented for different orders of phase shift keying (PSK) modulation schemes. Further, a detailed comparative analysis with the existing detection techniques for UL NOMA like SIC and least reliable symbol based ordered-successive interference cancellation (LRS-OSIC) is illustrated in terms of error rate and the computation complexity. The obtained results prove that the proposed RS-OSIC detection method for UL NOMA outperforms other existing techniques and closely matches with the best achievable error performance as accomplished by the optimal maximum likelihood (ML) decoder.